This was a quote from Dynon technical support staff regarding installing only 2 EGT probes with their D120 equipment ...After consulting with the Rotax gurus over at Lockwood Aviation (and they in turn consulted with Rotax technical support), we learned that of all the things one can glean from EGTs, the one that is most useful on the 912 is the ability to detect carbs out of sync. This requires only one EGT per bank. Additionally, on the 912, you can often see quite very different EGTs between the front and the rear pairs - as much as a few hundred degrees. This is inherent in the operation of the engine, and Rotax has seen people confused by the behavior when all four are monitored. In fact, measuring EGT isn't a requirement on the 912 per Rotax spec.
I am gonna try to ping Leading Edge Air Foils folks here close by in Wisconsin and see what's their opinion on this.
Anyway, I am going off on Wednesay for various engine and other maintenance + ADSB install and some other minor avionics work to these guys :http://www.midwestskysports.com/
I will ask them about this issue as well and will let you know ...